1. Field
Apparatuses and methods consistent with exemplary embodiments relate to a camera system that reduces dome ghosts in photographed images and a photographing method using the camera system.
2. Description of the Related Art
Surveillance cameras are usually installed in government offices, border lines, coastlines, and business places, such as companies or banks, which require security. In some cases, surveillance cameras are also installed outside to monitor traffic in real time. In this case, a surveillance camera system uses a transparent dome cover to protect a camera from rainwater, moisture, dust, and foreign matters.
The camera may be disposed to rotate with respect to a base in a pan and/or tilt direction in order to photograph a wide area, and may have a zooming function.
However, when the camera is exposed to strong light (e.g., sunlight) incident in a photographing direction, the light may be reflected from at least one of a plurality of lenses included in the camera after passing through the transparent dome, and then reflected again from the dome upon reaching the inner surface of the dome. As a result, the light reflected from the inner surface of the dome may reach the camera.
This problem may occur when light is incident at an angle between 10° and 30° with respect to an optical axis of a lens system included in a camera. This problem may occur at various angles according to installation environments, distances between a camera lens and a dome cover, and diameters of the dome cover. When the aforementioned problem occurs, an unintended spot, namely, a dome ghost, exists on a captured image. The unintended spot may distort image information required in a surveillance area by users, cause an error to image processing due to partial strong light, or degrade speed and performance.
Light irregularly reflected by the surface of a target to be photographed due to a strong light source enters the camera and renders ambient light relatively dark. During photography in an automatic exposure mode, an image of a surveillance target or an image of the periphery of the surveillance target is rendered relatively dark, and thus accurate image information may not be obtained.